Multimedia card (MMC) is a high capacity flash memory circuit module, which can be coupled to an electronic information platform such as personal computer (PC), personal digital assistant (PDA), digital camera or multi-media browser, to store various digital multi-media data e.g. digital photo data, video data or sound data. The specification of current MMC complies with the MMCA (multimedia card association) standards.
MMC package is a small scale integrated circuit (IC) device having a memory chip and/or a controller chip to store and process the multi-media data such as digital pictures and image data. The memory chip and/or controller chip are/is mounted on a chip carrier such as substrate or lead frame that mediate the electrical connection between the chip(s) and an external device to the chip(s) to operate. Conventional MMC packages have been disclosed in U.S. Pat. No. 5,677,524 entitled “Chip Card and a Method for Producing it”, U.S. Pat. No. 6,040,622 entitled “Semiconductor Package Using Terminals Formed on a Conductive Layer of a Circuit Board”, and Japanese Patent No. 62-239554 entitled “IC Card Type EP-ROM Structure”, which are incorporated herein by reference.
FIGS. 1A to 1C show the fabrication processes for a conventional MMC. Referring to FIG. 1A, the first step is to prepare an array of integrally formed substrates 10. Each of the substrates 10 includes at least one chip attach area 11, a plurality of passive component attach areas 12, and a plurality of electrical connection pads 13. The electrical connection pads 13 each extends from a top surface to a bottom surface of the substrate 10 to serve as contacts for external electrical connection for the MMC. The MMC to be fabricated is predetermined to have standard dimensions of 32 mm (length)×24 mm (width)×1.4 mm (height), and thus each substrate 10 is sized 30.25 mm (length)×21.25 mm (width).
Referring to FIG. 1B, a plurality of passive components 30 such as resistors, capacitors and/or inductors are mounted on the passive component attach areas 12 on each of the substrates. Then, at least one chip 20 is mounted on the chip attach area 11 of each of the substrates 10, and a wire-bonding process is performed to form a set of bonding wires 40 such as gold wires for electrically connecting the chip 20 to the electrical connection pads 13 on each of the substrates 10. Subsequently, an encapsulation process is carried out to form an encapsulation body 50 on each of the substrates 10 to encapsulate the corresponding chip 20 and bonding wires 40. And a singulation process is performed to separate apart the integrally formed substrates 10.
Referring to FIG. 1C, a cover 60 is attached to the encapsulation body 50 on each of the substrates 10 via an adhesive layer 51, wherein the cover 60 forms a receiving space 61 to receive the corresponding substrate 10 and encapsulation body 50 therein. This thereby completes the fabrication for the MMC. FIG. 1D shows a bottom view of the fabricated MMC, having the electrical connection pads 13 exposed to serve as contacts for external electrical connection.
Since the predetermined dimensions of the MMC is 32 mm (length)×24 mm (width), the cover 60 should have the same dimensions of 32 mm (length)×24 mm (width), and the receiving space 61 is sized 30.25 mm (length)×21.25 mm (width) corresponding to the substrate 10.
However, the above fabrication method has a significant drawback that the size of substrate 10 is relatively much larger than that of the chip 20, making the fabrication cost undesirably increased. Moreover, the cover 60 is correspondingly sized to form a sufficient receiving space 61 for receiving the substrate 10, thereby difficult to further reduce the profile of the MMC. Since the chip 20 is relatively much smaller than the substrate 10, some part of the receiving space 61 is waste, which is unfavorable for high integration development of packaging technology.
Therefore, the problem to be solved here is to provide a MMC package that can be cost-effectively fabricated with high integration.